Alkylene oxide adducts of an organic compound having active hydrogen or derivatives thereof are widely used as solvents, surfactants, or various chemical intermediates. In particular, alkylene oxide adducts obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to alcohols, fatty acids, fatty acid alkyl esters, amines, alkylphenols, or the like are widely used as nonionic surfactants.
For example, a fatty acid alkyl ester alkoxylate obtained by adding an alkylene oxide to a fatty acid alkyl ester and an alcohol alkoxylate obtained by adding an alkylene oxide to an alcohol are frequently used as a washing component of a detergent.
Examples of a method for manufacturing the alkylene oxide adduct include a method in which an alkylene oxide is added to a fatty acid alkyl ester or an alcohol in the presence of an alkoxylation catalyst.
In the above manufacturing method, it is known that the properties of the alkylene oxide adduct to be obtained and the amount of by-products produced vary depending on the alkoxylation catalyst. For example, in a case where an alkaline catalyst is used as the alkoxylation catalyst described above, it is possible to obtain an alkylene oxide adduct having a wide adduct distribution of alkylene oxide. In a case where a solid metal catalyst is used as the alkoxylation catalyst described above, it is possible to obtain an alkylene oxide adduct having a narrow adduct distribution of alkylene oxide. Therefore, studies on alkoxylation catalysts are being actively conducted in order to obtain a desired alkylene oxide adduct.
PTL 1 discloses an alkoxylation catalyst obtained by reacting at least one compound selected from the group consisting of an alkaline earth metal salt of a carboxylic acid, an alkaline earth metal salt of a hydroxycarboxylic acid, an oxide of an alkaline earth metal, and a hydroxide of an alkaline earth metal with sulfuric acid in a liquid dispersion medium. It is described that the amount of by-products produced is reduced in a case where the alkylene oxide adduct is manufactured using the alkoxylation catalyst.